The present invention relates to a fuel level measuring method for use in an automobile and, more particularly, to a fuel level measuring method which may be implemented with a microcomputer.
As disclosed in U.S. Pat. No. 3,842,673 to John W. Riddel, in a conventional fuel level meter for an automobile, the fuel level in a fuel tank is converted into an output signal by means of a sensor having winding type resistor with a sliding contact. With a predetermined resistance value of the sliding resistor, a current coming from a constant voltage source is controlled to cause a pointer to point to the fuel level measured. Practically, the shape of the fuel tank is not uniform and the fuel level and the moving angle of the sensor are not always in a linear proportional relation to each other. Therefore, some adjustment must be made to the moving angle and the output resistance of the winding resistor, so as to set up a linear relation between the fuel level and the fuel level value indicated by the pointer.
The total of the errors accumulated through the signal process ranging from the sensor to the pointer is great. For this reason, in actual practice, the indication of the fuel level by the pointer is a mere approximation of the actual fuel level. On the other hand, a driver requires information concerning the fuel level in the fuel tank with the best possible accuracy, since he uses such information more frequently, as compared with other information for driving the automobile.